Particle accelerators are devices that energize ions and drive them into a target. Neutron generators are a specific use of particle accelerator that produce neutrons by fusing isotopes of hydrogen. A fusion reaction takes place by accelerating either deuterium, tritium or a mixture of the two isotopes into a target that also contains deuterium, tritium or a mixture of the isotopes. Fusion of deuterium atoms results half of the time in formation of a 3He ion and a neutron, the other half resulting in the formation of a 3H (tritium) ion and a proton. Fusion of a deuterium and a tritium atom results in the formation of a 4He ion and a neutron.
Particle accelerators and neutron generators have numerous applications in medicine, imaging, industrial processes (e.g., on-line analyzers, metal cleanliness, raw materials, Al base catalysts, energy production), material analysis, safeguards (e.g., nuclear material detection), research, education, exploration, security (e.g., explosive detection, chemical weapon detection, contraband detection), and ion implantation.
Historically, neutron generation has involved incredibly complex and expensive systems and employed approaches that either generate or use undue levels of hazardous materials or provide insufficient neutron output to satisfy commercial needs. Radioactive sources capable of producing high neutron levels contain hazardous quantities of radiation requiring many safety considerations. Neutrons can also be produced by nuclear reactions with accelerators (e.g., cyclotrons, Van de Graaff accelerators, LINAC) with large yields, but at substantial cost and complexity of operation. Use of neutron generators using deuterium-tritium (DT) reactions addressed some of the safety problems, but required sealing because of tritium content and have a typically short lifetime. Attempts at using deuterium-deuterium (DD) neutron generators have met with limited success because of the ˜100× lower fusion cross section of the DD reaction compared to the DT reaction.
The cost, lack of efficiency, safety concerns, and lack of durability of existing systems has kept them from finding use in many commercial applications that could benefit from neutron generators. Addressing these problems in this field has been very complex and routine optimization or alteration of existing systems has failed to provide meaningful or practical solutions.